Astrometry.net solvers should return the jobid

[alsimoneau]

Currently, both solvers call monitor_submission before returning. This has for consequence that the only way to obtain the jobid, which is required to download the result files from the server, is to force a TimeoutError. This leads to code that is hard to read and potentially unreliable if the solve is particularly fast.

For example, here is a code sample adapted from the documentation:

submission_id = None

while True:
    try:
        if not submission_id:
            wcs_header = ast.solve_from_image('/path/to/image.fit', solve_timeout=1)
        else:
            wcs_header = ast.monitor_submission(submission_id, solve_timeout=120)
    except TimeoutError as e:
        submission_id = e.args[1]
    else:
        break

I propose that the solvers directly return the jobid and let the user call the monitor_submission method themselves. Here is the same code with the proposed change:

submission_id = ast.solve_from_image('/path/to/image.fit')

while True:
    try:
        wcs_header = ast.monitor_submission(submission_id, solve_timeout=120)
    except TimeoutError as e:
        continue
    else:
        break